CD56dimCD16high and CD56brightCD16− cell percentages associated with maximum knee extensor strength and incidence of death in elderly

Abstract

Physical fitness is an indicator of systemic well-being in humans. Little is known about the role of physical fitness for maintaining systemic health in the elderly. Here, we study elderly subjects to determine the relationships between physical fitness and CD56 and CD16 surface NK cell markers on peripheral blood lymphocytes, as well as to analyze the relationship between the surface markers and incidence of death. We selected 253 independent elderly subjects (122 female; 131 male) who were 79–80 years old. Subjects having a higher proportion of CD56dimCD16high within CD56+CD16+ cells, or ration of CD56dimCD16high and CD56dimCD16− cells had a significant positive correlation with maximum bilateral knee extensor strength/weight (kg) (r = 0.425; P < 0.0001 or r = 0.323; P < 0.0001). In contrast, an increased proportion of CD56brightCD16− cells within lymphocyte significantly negatively correlated with the maximum bilateral knee extensor strength/weight (kg) (r = −0.290; P = 0.0004); and these subjects had a significantly lower mortality during the 5 years following measurement of death. Therefore, we found that a synergistic effect of the right and left leg muscle strength was associated with proportion of matured NK and NKT cells and induced a low proportion of CD56brightCD16− cells within lymphocyte. Moreover, the low proportion of CD56brightCD16− cells was associated with incidence of death. In conclusion, measurements of physical fitness, the proportion of CD56dimCD16high within CD56+CD16+ cells, the ratio of CD56dimCD56high and CD56dimCD16− cells, and the proportion of CD56brightC16− cells in lymphocytes are important indicators to check elderly health.